build(deps): Bump dependency protoc to v29

.tool-versions

@@ -13,7 +13,7 @@
 # Protoc is used (only) by tools/protoc/protoc.bash
 # to generate *.schema.json from *.proto; the Bazel
 # rules_proto (downloads and builds) its own protoc.
-protoc 25.3
+protoc 29.2
 
 # TODO protolint here instead of installing it in test.bash
 # when https://github.com/spencergilbert/asdf-protolint/issues/37 is fixed